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Chrysler Repair/neon hiccups / dies when attempt to reverse; code 21


i have a neon 1996 2lt sohc. i just replaced the coolant sensor and the ignition coil pack. the gives a hard start idles when i attempt to reverse it moves slightly, changes idle sound and shudders then die.  the only code i remain with is 2155 which is oxygen sensor. in forward gear it accelerates ok and after i assume getting properly hot i start getting hiccups like it momentarily loses power sometimes it can an oxgyen sensor cause this or theres something else and its throwing a sensor code to confuse

ANSWER: Hi Tony,
I don't find the 2155 code in my manuals. Are you sure that is the correct number and if so what does your reference described it to be? You can erase the codes by disconnecting the battery briefly and then recheck for codes after driving it for a while. I would work on the code items first before assuming something else is wrong. Let me know the number/name again, please.
Please 'rate/nominate' my answer/me (see the PS below).

---------- FOLLOW-UP ----------

i used the online to try and find out what it could mean. i remember you once said 55 is end of reading and so it means 21 might be the trouble code

11 Timing belt skipped 1 tooth or more from initial learned value, Intermittent loss of either camshaft or crankshaft position sensor, No crank reference signal detected during engine cranking
12 Direct battery input to PCM was disconnected within the last 50 key-on cycles
13 No change in MAP from start to run
14 MAP sensor voltage too low
15 No vehicle speed sensor signal
16 Battery voltage lost while engine running (may not apply to Neons)
17 Closed loop temp not reached or engine cold too long
21 Oxygen sensor problem, upstream or down stream (there were two sensors)
22 Engine coolant temp sensor out of range

Original is at Chrysler - Plymouth - Dodge Neon Computer Code List
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Ok Tony,
I had assumed that the 4-digit number (2155) was obtained with an OBD-II reader because those are 4 digits. The code 21 is an OBD-I and you presumably got that via the ignition key.
My suggestion would be to go to a nationwide auto parts store, such as Autozone, and ask for a free fault code readout using a plug-in code reader. That way you will get one of 7 possible codes that will tell us which of the two sensors is acting up and in what manner (the number will be between 0131 and 0139). You could probably buy the proper sensor based upon the number and replace it, or inspect the wiring of that sensor and the wiring harness for damage and then decide if that looks ok then buy the sensor.  Once that code is resolved and no longer present (disconnect the battery briefly, then drive some more (but you will get a 12 code temporarily due to the battery disconnect) see whether the engine then runs properly.
Please 'rate/nominate' my answer/me as I am in competition to be 'volunteer of the month'.

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Roland Finston


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